1. Field of the Invention
The invention relates to a tire pressure sensor that is integrated in a single one-piece housing with a valve stem and which is mountable to a tire rim in one step.
2. Description of the Related Art
Electronic tire pressure sensors are becoming increasingly common in motor vehicles. Beginning Sep. 1, 2005, the National Highway Traffic Safety Administration (NHTSA) will phase in regulations that will require that manufacturers install tire pressure sensors in many passenger vehicles. See, e.g., Federal Motor Vehicle Safety Standards; Tire Pressure Monitoring Systems; Controls and Displays, 49 C.F.R. parts 571 and 585.
Various configurations for an electronic tire pressure sensor are described in the art, but most share the common basic features of: being coupleable to or part of a tire rim or a tire valve stem which fits into an opening in the rim to allow the tire to be filled with air; having an electronic pressure sensor for sensing the pressure in tire; and having a radio frequency (RF) transmitter for transmitting a radio signal indicative to the sensed pressure to the vehicle's computer. Such electronic tire pressure sensors are mounted inside the space between the tire and the rim and must be able to withstand the considerable g-forces that result from tire rotation. Most of the various configurations of tire pressure sensors in the art are the result of efforts to meet these requirements in ways that minimize the costs associated with the sensor systems and their installation. Various examples of electronic tire pressure sensors are described in U.S. Pat. Nos. 6,005,480, 5,853,020, 4,734,674, and 6,722,409, which are hereby incorporated by reference in their entireties.
A drawback to presently existing tire pressure sensors is that their installation requires an additional step beyond what is required to install a valve stem and/or valve stem assembly in a tire rim. For example, it is typical that the valve stem portion be first installed in the rim, and then the pressure sensor portion affixed to it in a separate step. As a further drawback, such schemes require the tire pressure sensor to comprise different pieces. It would be desirable to have an electronic tire pressure sensor that is as simple to install as a conventional valve stem, and which is fully integrated with the valve stem as a single piece. This disclosure provides such an embodiment.